1. Field of the Invention
The present invention concerns a method and device to determine a failure in at least one gradient coil of a magnetic resonance tomography system with current-supplying gradient cables.
2. Description of the Prior Art
Magnetic resonance apparatuses to examine patients by magnetic resonance tomography (MR) in particular are known from DE 103 14 215, for example.
Modern magnetic resonance systems operate with coils that emit radio-frequency pulses to excite nuclear spins so as to emit magnetic resonance signals and/or to receive the induced magnetic resonance signals. A magnetic resonance system typically has a permanent magnet or (more often) a superconducting coil to generate an optimally homogeneous magnetic field—known as a basic magnetic field (HO)—in an examination region. A magnetic resonance system also typically has a large coil that is normally permanently installed in the MR apparatus—known as a whole-body coil (also called a body coil or BC)—and multiple small local coils (also called surface coils or local coil). To acquire information (data) from which images of a patient can be generated, selected regions of the subject or patient to be examined can be read out with gradient coils for three axes (for example X, Y approximately radial to the patient, Z in the longitudinal direction of the patient). The spatial coding in magnetic resonance tomography is typically achieved with the use of a gradient coil system with three independently controllable gradient field coil systems that are magnetically orthogonal to one another. The orientation of the coding plane (‘gradient field’) can be freely selected by superimposing the three freely scalable fields (in the three directions X, Y, Z).